1. Field of the Invention
The present invention relates to a confocal microscope.
2. Description of Related Art
Japanese Laid Open Utility Model Publication No. H6-16927 discloses a confocal microscope in which the quantity of the light flux having passed through a confocal aperture is detected with a light detector by condensing illuminating light on a specimen such as an organic specimen and condensing onto the confocal aperture surface the light flux from the light converging area on the specimen. With this confocal microscope, the light quantity is detected while scanning the specimen with the light converging area (spot) in order to obtain a two-dimensional image of the specimen.
A pinhole member is disposed on the confocal aperture surface. The pinhole member allows only the light beam condensed inside a pinhole (opening) to be transmitted and cuts off the rest of the light. For this reason, only the light beam from a position at a specific height in the specimen enters the light detector and the light beams from positions with other heights do not enter the light detector. Thus, the confocal microscope makes it possible to observe only the image of a thin layer of the specimen located at a specific height in the specimen (sectioning).
In order to alter the thickness of the layer to be observed, i.e., in order to alter the sectioning resolution, the diameter of the opening at the pinhole member is adjusted. The sectioning resolution is lowered by increasing the opening diameter, whereas the sectioning resolution is raised by reducing the opening diameter.
The microscope disclosed in Japanese Laid Open Utility Model Publication No. H6-16927 includes a mechanism for controlling the pinhole diameter (opening diameter) of the pinhole member or a mechanism for selectively inserting/withdrawing one of a plurality of pinhole members having different pinhole diameters into/out of the optical path, so as to allow the user to freely adjust the sectioning resolution in correspondence to the specific type of specimen being observed.
However, a confocal microscope having a mechanism for controlling the pinhole diameter is bound to be large and costly, whereas the mechanism for allowing one of a plurality of pinhole members to be inserted into or withdrawn from the optical path is bound to complicate the process of positioning the pinhole in the optical path.